The present invention relates to a car type conveyor suitable for the conveyance of large bodies on a car assembly line or the like.
A conventional car type conveyor for conveying large bodies includes a pair of guide rails extending on a floor. Carriages run on the guide rails and can be driven by the propulsive force transmitted from driving runners, which are fitted under the floor. Another conventional car type conveyor for conveying large bodies includes carriages, which run along a path extending on a floor. Each of these carriages has a frictional surface formed in parallel to the path. Friction drivers are fitted at intervals along one edge of the path and each include a frictional wheel for compressive contact with the frictional surfaces of the carriages. Each of the conventional conveyors, inclusive of the means for driving its carriage, is high in structure. It is difficult to lower each of the conventional conveyors without using the space under the floor.
The object of the present invention is to provide a car type conveyor low in structure and suitable for the conveyance of large bodies on it.
A car type conveyor according to the present invention includes a guide rail, a friction driver, a runner and a carriage. The guide rail extends along one edge of a running path. The friction driver is fitted in the running path and includes a frictional wheel. The runner is guided by and moves along the guide rail. The runner has a frictional surface formed on it for compressive contact with the frictional wheel. The carriage includes at least one wheel and moves along the running path. The runner and one of the right and left sides of the carriage are connected together in such a manner that the top of the runner is higher than the position at which the carriage supports a body.
It is possible to lower the whole conveyor and the carriage by:
1. positioning the runner, which frictionally drives the carriage, on one side of the carriage and making the top of the runner higher than the position at which the carriage supports a body (the bottom of the runner may be higher than, equal in height to or lower than the position at which the carriage supports a body);
2. causing the wheel of the carriage to bear at least part of the load on the carriage so that the runner and the guide rail may be lower in strength, thereby enabling the runner to be lower in structure: and
3. forming the frictional surface, which may be continuous along the length of the runner, which can be frictionally driven, so that the runner can easily be low in structure.
The carriage may include an inverted L riser protruding from its side adjacent to the runner. The riser includes a horizontal top extending over and connected to the runner. This makes it easy to support the side of the carriage on the runner. This also makes it possible to provide a simple and stable structure where the guide rail is supported directly over a floor.
Alternatively, the carriage may include a substantially horizontal extension extending from its side adjacent to the runner. The extension hangs from the bottom of the runner. This enables the carriage to be flat and simple and the cost to be low. In this case, even if the runner bears part of the load on the carriage, the runner can easily be lower in structure and can smoothly run.
The conveyor may include a number of runners, which are guided by the guide rail. Each runner has a frictional surface and connected to a carriage, that moves along the running path. Each runner may include a load bar for thrust that is longer than the body supported on each carriage. The conveyor may also include a number of friction drivers fitted in the running path. Each friction driver includes a frictional wheel for compressive engagement with the frictional surfaces of the runners. The load bar of the runner driven by each friction driver can thrust the load bar of the preceding runner out of engagement with the friction drivers, without causing the bodies on the associated carriages to interfere with each other. This makes it possible to greatly reduce the number of friction drivers. The frictional surface of each runner may be formed on one side of the associated load bar, which is necessary for thrust. This makes the runners simple in structure.
The carriage may include at least one pair of right and left wheels for preventing the load on it from acting on the runner. These wheels support the carriage and prevent the load on it from acting on the runner and the guide rail. This enables the runner and the guide rail to be small, making it easier to lower the height of the conveyor.
The carriage may include a wheel for sharing the load on the carriage with the runner. This wheel rolls on a running surface in the running path. In comparison with the case where the load on the carriage does not act on the runner, the carriage wheel prevents the runner from being overloaded often even if the smoothness of the running surface is slightly low. This enables both of the runner and the carriage to smoothly run.
The carriage may include a middle wheel fitted near the midpoint between both its sides and an outer wheel fitted near its side far from the runner. The middle wheel and one of the outer wheel and the runner can bear the load on the carriage. The middle and outer wheels roll on a middle running surface and an outer running surface respectively of the running path. If the middle wheel is kept in contact with the middle running surface, one of the outer wheel and the runner can keep the carriage in a position in which the carriage supports a body. This enables the carriage to stably run. In this case, it is easy to install the guide rail and form the outer running surface.
The wheels of the carriage may be fitted substantially at the middle position between the front and rear of the carriage. In this case, the runner and the guide rail regulate the direction in which the carriage is oriented and the position in which the carriage supports a body. This enables the carriage to run smoothly in a horizontal curved passage of the running path.
The carriage may be a folding carriage including a base part and a movable part. One side of the base part is supported by the runner. One side of the movable part is connected to the other side of the base part in such a manner that the movable part can be folded over the base part. Each of the base part and the movable part includes a wheel. The wheels of the two parts roll on a running surface in the running path.
While the folding carriage is conveying a body, the body can be supported stably on the carriage unfolded to have a necessary width extending over the base part and the movable part. While the folding carriage is empty, it is possible to fold the movable part over the base part to greatly reduce the width of the carriage, which extend laterally from the runner. Even with the movable part folded, the carriage can run with the base part supported stably by its wheel and the runner, which is supported by the guide rail. Accordingly, although the folding carriage is suitable for the conveyance of a car body or another large body, it is possible to increase the efficiency of utilization of the floor by greatly reducing the floor area occupied by the passage of the running path where the carriage is empty.
The movable part of the folding carriage may be narrow so as not to be folded over the runner. This enables the conveyor to be low in structure with the carriage folded. This also enables the path passage where the carriage is empty to extend in a low space. This further enables the folded carriage to run safely without a means provided for locking the movable part in a folded position.
Alternatively, the movable part of the folding carriage may be wide so as to be folded over the runner. In this case, the base part of the folding carriage may be sufficiently narrow so that the path passage where the carriage is empty can be narrower.
The wheel of the base part of the folding carriage may be fitted near the side of the base part that is adjacent to the movable part. The wheel of the movable part of the folding carriage may be fitted near the side of the movable part that is far from the base part. In this case, while the movable part is folded over the base part, the base part is supported by its wheel and the runner.
The wheels of the folding carriage are positioned substantially at the middle position between the front and rear of the carriage. In this case, the runner and the guide rail regulate the running direction and the horizontal position of the carriage.
The base part of the folding carriage may include an inverted L riser rising on its side supported by the runner. The riser includes a horizontal top extending over and connected to the runner.
The base part of the folding carriage may include a substantially horizontal extension extending from the side thereof supported by the runner. The extension hangs from the bottom of the runner.
The running path may be endless and include a first passage and a second passage. The folding carriage may run with a body loaded thereon in the first passage. The folding carriage may run without a body loaded thereon in the second passage, with the movable part folded over the base part. The inner edges of the two passages are adjacent to each other. The guide rail may be endless and extend along the inner edges. This makes it easy to lay out the two passages in parallel on or over a narrow beltlike floor.